Advancing Guidelines for the Design of Tooth-Supported Surgical Guides with Free-End Configurations: A Simulation Study of the Influence of Surgeon's Hand Force

Numerous studies show that the use of dental guides that rest on the patient's teeth improves the precision of implant placement, but the currently developed procedures and selected materials are still not perfect and could result in deviations from the planned implant position. The impact of the surgeon's hand force on the deformation of dental guides during implant placement has not yet been investigated or documented. In this study the behavior of the 3D guide model is evaluated by FEA analysis to validate the influence of the force of the surgical hand on dental guides due to their application. FEM simulation of deformation and stress was designed for four different types of dental guides that are supported on teeth for different ways of supporting the guide due to the action of the surgeon's manual force (chosen arbitrarily 30 N). The finite element simulation method performed on 5 sets of commonly used biocompatible polymer materials, Stratasys MED610 and VeroGlaze MED620, EOS PA2200, Formlabs FLSGAM01 and Stratasys ULTEM 1010, successfully numerically quantified the deformation of the dental guide caused by the surgeon's arbitrarily manual forces during manipulation. Based on the conducted analyses, guidelines were proposed for improving the design of guides, with an emphasis on optimal selection of supports, stability on the patient's anatomy, and reduction of deformations, thereby increasing the accuracy of implant placement. It was found for all four designs of dental guides that the deflection depends on the size of the arm, i.e. the distance of the support from the point of application of the force. As a result of the study, diagrams were created that serve as guidelines for the design of beam (A and A1) and cantilever (B and B1) versions of dental guides that rely on teeth. Guidelines for enhancing guide design were put out based on the analyses that were carried out, with a focus on the best choice of supports, stability on the patient's anatomy, and minimization of deformations in order to improve implant placement accuracy.